This application is based on and claims priority to Japanese Patent Application No. 11-057642 filed Mar. 4, 1999 and Japanese Patent Application No. 11-093359 filed Mar. 31, 1999. The entire contents of these applications are hereby expressly incorporated by reference.
1. Field of the Invention
This invention relates to a fuel injection control system for an engine, and more particularly to a fuel injection control system that is suitable for an outboard motor.
2. Description of Related Art
In order to improve engine performance and in particular fuel efficiency and emissions, many types of engines use a fuel injection system for supplying fuel to the engine. A fuel injection system often includes fuel injectors that directly inject fuel into an air induction device. The amount of fuel injected through the fuel injectors is determined by a control system, which usually includes an electronic control unit (ECU). Typically, the ECU determines the desired amount of fuel and the corresponding fuel/air ratio based upon the engine speed and load. The fuel injection system can therefore improve performance by precisely controlling the fuel/air ratio for each cycle of the engine and over a wide variety of engine running conditions.
There are, however, several problems with typical fuel injection systems. For example, when the engine is being started, engine speed cannot be determined until the engine completes one or more revolutions. Accordingly, fuel is not delivered to the fuel injectors immediately. This prevents the engine from operating immediately and requires the starter device to turn the engine longer. The problem is exacerbated if the engine speed is determined by measuring the rotation of the camshafts because the camshafts are often rotated at half the speed of the crankshaft.
Furthermore, when the engine is being started, the fuel/air ratio usually needs to be rich. To achieve this result, some engines include a starter signal device. The starter signal device generates a signal that indicates when the engine is being started. This signal is inputted into the ECU of the control system. When the signal indicates that the engine is being started, the ECU delivers the proper amount of fuel such that the fuel/air mixture is rich. The starter signal device adds an additional engine component to the engine. This increases the size of the engine and manufacturing costs. Additionally, the ECU must include an additional connector to receive the signal from the starter device. The additional connector increases the size and cost of the ECU.
Fuel injection systems are often used in outboard motors. Because outboard motors are often operated under harsh conditions, it often is desirable that they start quickly. Furthermore, it is well known in the art that outboard motors should be as compact as possible. Accordingly, it is especially important that outboard motor components be as small as possible and that the arrangement of outboard motor be as compact as possible.
Accordingly, there is a need for a for an improved fuel injection control system that enables the engine to start more quickly. There is also a need for a simplified control system that uses a fewer number of parts.
In accordance with one aspect of the present invention, an internal combustion engine comprises at least one combustion chamber formed by at least a first member and a second member that moves relative to the first member. The second member is coupled to an output shaft such that movement of the second member causes the output shaft to rotate. A fuel injector supplies fuel to the combustion chamber. The fuel injector includes an actuator to regulate an amount of fuel injected by the fuel injector. The internal combustion engine further includes a fuel control system that comprises a controller, which is connected to the fuel injector actuator, and a sensor, which is arranged to detect rotation of the output shaft. The sensor is adapted to produce a signal that is indicative of rotation of the output shaft and is connected to the controller. The controller is configured to output a control signal to actuate the fuel injector actuator when a signal is received from the sensor indicating that the output shaft has initially begun to rotate.
In accordance with another aspect of the present invention, an internal combustion engine comprises at least one combustion chamber that is formed by at least a first member and a second member that moves relative to the first member. The second member is coupled to an output shaft such that movement of the second member causes the output shaft to rotate. A fuel injector supplies fuel to the combustion chamber. The engine further includes a controlling means for starting the injection of fuel into the combustion chamber after the output shaft begins rotating as the engine is started.
In accordance with a further aspect of the present invention, an internal combustion engine comprises at least one combustion chamber formed by at least a first member and a second member that moves relative to the first member. The second member is coupled to an output shaft such that movement of the second member causes the output shaft to rotate. A fuel injector supplies fuel to the combustion chamber. The fuel injector includes an actuator to regulate an amount of fuel injected by the fuel injector. The engine further includes a fuel control system that comprises a controller, which is connected to the fuel injector actuator, and a sensor, which is arranged to detect rotation of the output shaft. The sensor is adapted to produce a signal that is indicative of rotation of the output shaft and is connected to the controller. The controller is configured to operate under an engine start routine when starting the engine and to determine when an engine reaches an engine start speed, which is indicative of the engine having started, so as to operate under a normal operation routine.
In accordance with still a further aspect, a method of starting an internal is provided. The combustion engine includes at least one a combustion chamber, a crankshaft, at least one camshaft, and at least one fuel injector. The method comprises sensing the rotation of either the crankshaft or the camshaft, determining an amount of fuel to be injected by the fuel injector toward the combustion chamber, and injecting the amount of fuel into the combustion chamber in response to the sensed rotation of either the crankshaft or the camshaft when the respective shaft initially begins to rotate as the engine is starting.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiment which follows.